Minor fixes. (#91)

* Get Bit: Make more terse

* Power of two: Allowed 1 as a valid power of 2.
Power of two: Removed unnecessary exception throwing.

* Fisher Yates: Made more terse

* Least Common Multiple: Fill undefined value

* Greatest Common Divisor: Fill undefined value.
Greatest Common Divisor: Make more terse.

src/algorithms/math/bits/getBit.js

@@ -4,5 +4,5 @@
  * @return {number}
  */
 export default function getBit(number, bitPosition) {
-  return (number & (1 << bitPosition)) === 0 ? 0 : 1;
+  return (number >> bitPosition) & 1;
 }